Iron Vs. Aluminum, the Final say!

[Maple Leaf]

Upside down dude.. lol

BTW that is some craziness going on in that fiero forum! :P

[caffeine]

I've been assured these are actually wheel horsepower and wheel torque numbers. Stock everything except the y-pipe. And my tune needs work with a wideband .

Edit: the max torque number isn't specified on the sheet but my friend told me its 252 ft. lbs.

[ericjon262]

http://www.fiero.nl/forum/Forum2/HTML/127251.html

This has made it all worth it. The light has been seen!

[caffeine]

Basically it seems his argument consists of "I made lots of power with iron heads" but the fact remains he could have made more with aluminum heads...

[carbon]

LOL... I do try to direct people with real 60* questions over here as often as I can...

[robertisaar]

i'm sure, i've been loosely following along, i'm just saying don't expect to bring enlightenment to those who do not want it.

[Superdave]

guys...... you're feeding the troll.

It's fun.

[ericjon262]

[robertisaar]

guys...... you're feeding the troll.

I'm not sure on what goes on with a dyno, but if the dyno is seeing engine speed and roller speed, I imagine it could account for the difference.

Doesn't matter if the dyno can see engine RPM, the mechanical advantage is still there, and skews the results.

I spoke with a dyno opertator at length, after a friend of mine dynoed his 1100 HP Firebird. Applying different compensation formulas to the same run we had his car making anywhere between 500 HP and 1600 HP. lol Dynos are not a very good comparison tool, but it's the easiest thing we have currently. Personally I don't care what the dyno tells me, as long as I get a smile across my face when I press on the loud pedal, that's all I care about.

[Superdave]

engine speed is calculated from drum speed on most dynos.

The shop I go to refuses to use a spark pickup to calculate RPM, instead they assume 1:1 gearing and put in the final drive ratio. It makes for a skewed graph. My pulls were in 3rd which is 1.38:1, the .94:1 4th gear pulls were pretty similar power wise but 145MPH on the rollers with 30 people around watching isn't very safe.


I put my car on another local dyno when i first built it, they used a spark pickup and the graph was much better. The car was so lean with the stock fuel pump and pre-00 FPR that we never made a complete pull. iirc it was like 240WHP @ 4500 RPM with a 14:1 AFR.

[ericjon262]

Why is it that people don't understand the mechanical advantage of using a lower gear than a 1:1 gear on a chassis dyno?

EVERY time I have seen a dyno print out from someone that used a gear that is not 1:1, the torque is high, but HP is low, this is EXACTLY the reason the transmission with multiple gear sets was invented, to give mechanical advantage, namely for acceleration.

I'm on another site where there are similar people, the ones that will challenge you to prove them wrong and then when you do, through proven math and empirical evidence, will then change the subject or say that the person proving them wrong just doesn't understand.

I'm not sure on what goes on with a dyno, but if the dyno is seeing engine speed and roller speed, I imagine it could account for the difference.

[Superdave]

He's also got DOHC pistons in his 3.4, assuming .040 headgaskets it's at 9.95:1 SCR (Also assuming the heads haven't been shaved or the block decked). With a stock cam no wonder it's making good torque. Still only around 170-180 HP though.


When we put together Clang's 3500 for his Z24 it made monster torque on the stock cam. SCR was around 11:1, ran fine on pump gas and was a blast to drive (when something else wasn't breaking on the car). 3500 with a ported top end, heads shaved .020 and .040 camaro gaskets.

Why is it that people don't understand the mechanical advantage of using a lower gear than a 1:1 gear on a chassis dyno?

EVERY time I have seen a dyno print out from someone that used a gear that is not 1:1, the torque is high, but HP is low, this is EXACTLY the reason the transmission with multiple gear sets was invented, to give mechanical advantage, namely for acceleration.

I'm on another site where there are similar people, the ones that will challenge you to prove them wrong and then when you do, through proven math and empirical evidence, will then change the subject or say that the person proving them wrong just doesn't understand.

[ericjon262]

my favorite part is that he won't answer this:

Originally posted by ericjon262:


LTx based heads have been proven performers for years, in fact, they've been that way since the beginning, they are hands down, no questions asked the best castings GM produced for a V8 with a 23*valve angle, and now you're bringing up LT1's, which has no basis for comparison on the subject as they had roller cams and aluminum heads from their onset.

When I asked about the roller cam V flat tappet L03, you refuse to answer, which confuses me, because you make the claim that the roller cam is where all of the improvement is on the GEN 3 motor, but yet these two otherwise identical motors don't have different outputs, and the only difference is the roller cam.

his argument is that the roller cam is the only improvement on the GEN 3 motor, so I show him the LO3 305 that was installed in 3rd generation F-bodies, and trucks, the trucks got a flat tappet cam, the cars got roller cams, but were otherwise identical. if there were an appreciable difference in power, GM would have marketed the camaro and firebirds with more power, it's easier to sell a car with 190 hp vs 170...